Fuel pump



April 4, 1961 BANKER 2,977,886

FUEL PUMP Filed April 13, 1955 3 Sheets-Sheet 1 FIG 1 H G1 2 mmvroa.Oscar J2. Ban/(er April 4, 1961 O BANKER 2,977,886

FUEL. PUMP Filed April 13, 1955 a Sheets-Sheet 2 1N VEN TOR. 7 Oscar J1.flan/(er :4 array 0. H. BANKER FUEL PUMP April 4, 1961 3 Sheets-Sheet 3Filed April 15, 1955 IN VEN TOR. OscarJz. flan/(er FIG. 1%

FUELPu r "and Apr. 13, 19 s, Ser. N6. 501,019 7 Claims. 01.103-11 Thisinvention relates to fuel pumps for internal com bustion engines used topower automotivevehicles.

It is a well known fact that when the. fuel pumps of present daygasoline-burning internal combustion engines in automotive vehiclesbecome heated above a predetermined temperature,dependingupon thecharacteristics of the particular gasoline used, the gasoline will forma vapor which, because of its compressibility, interferes with thefurther functioning of the pump to transfer gasoline from the fuel tankto the carburetor of the engine. This condition is generally referred toas a vapor lock. Without fuel, the engine ceases to operate and cannotbe made to resume its operation until the temperature of the fuel isreduced sufliciently to eliminate its spontaneous vaporization. Sinceeffective cooling media .are notv usually readily available on the spot,the vehicle is immobilized until air currents perform the necessarycooling operation. On a hot day, this is a slow process.

It is. an object of this invention to provide a-fuel pump for aninternal combustion engine of such design that its operation will not bematerially affected by the presence of vapor. i

Internal combustion engines used in automotive vehicles may be dividedroughly into those operating on the fuel injection principle, such asthe diesel engine, and those operating on the pre-mixed fuel-and-airprinciple such as the ordinary gasoline engine equipped with acarburetor. The fuel injection type operates at higher pressures thanthe carburetortype, the former utilizing a light oil at approximately 75pounds per square inch pressure, where as the latter should not feed thefuel to the carburetor at pressures exceeding 5 pounds per square inch.Both forms, however, are subject to vapor lock, the diesel type beingparticularly susceptible after a long uphill climb,

followed by a downhill coast against the engine during which the fuel isconverted into a frothy mixture containing a large amount of air whichrenders the mixture compressible and hence incapable of being operatedupon by the pump to cause a flow of the liquid fuel to the injectionnozzles of the engine.

It is another object of this invention, accordingly, to.

provide a fuel pump for automotive vehicle internal combustionengineswhich may be utilized either with high pressure fuel injectionsystems, or with relatively low pressure carburetor fuel feedingsystems, and which nevertheless will be equally effective to pass anyvapor, entrained air, or frothy mixture through the fuel feeding system.i r

A more specific object of this invention is the provision of a pump fora fuel feeding system for an internal combustion engine wherein the pumpis provided with means for minimizing the feed-back of vaporized fuelfrom the pressure side 'of the pump to the intake side thereof andthereby tominimize the conditions under which a vapor lock forms. i

. A specific object-ofthisvinvention-is the provision of a side-sealingmeans fora gear type pump which shields Patented Apr. 4, 1961 thereon bythe side sealing'means, thereby reducing friction losses within thepump, and wear'of both the sidesealing means and the sides of the gearsin contact there- With.' H

I have found that most of the ineffectiveness of fuel pumpslunder vaporlock conditions arises because the pumps themselves are so ineflicientthat they are unable to create a sufficiently high vacuumin the presenceof vapor to cause the fuel to flow from the tank to the pump, and it is.accordingly a further object of this invention to provide a fuelpumpfor an internal combustion engine, the pump being of such highvolumetric efficiency as to draw fuel from a tank despite the presenceof vapor in the pump, even under such relatively low operating speeds ofthe pump as are encountered when the engine is turned over by a starter.

A feature of this invention isa design of fuel pump for an internalcombustion engine wherein the pump is free of pockets. in which vapormay be trapped.

These and other objects and features of this invention will becomeapparent from the following detailed descriptibn when taken, togetherwith the accompanying drawings in which: 7

Fig. 1 may be considered an elevational view of a pump. madev in.accordance with this invention and designed particularly for use withliquid fuel injection systerns; 1

' of the end cover,

Fig. 2 is a transverse section through the pump taken along line 2-2 ofFig. 1 andin the direction of the ar-i rows at the ends thereof; V I vFig. 3 is a plan view 'ofthe assembled pump of Fig. 1;?

Fig. 4 is an elevation in section of the pump of Fig. 1 taken along line4-4 of Fig. 2; i i Fig. 5 is an elevation of thecover plate for the pumpof Fig. 1 taken along lines.5-5 of Fig. 2; a I

Fig. 6 is a fragmentary enlarged section of a portion the section beingtaken along line 6-6 ofFig.5; j

, Fig. 7 may be considered a plan view of a fuel pumpparticularlydesigned for low pressure fuel systems using a carburetor for mixing thefuel and air; Fig. 8 is an elevation in section of the pump of Fig. 7,the section being taken along line 8-8 thereof and look-'. ing in thedirection of the arrows at the ends of said line. I Fig. 9 is an endelevation of the pump of Fig. 7; Fig. 10 is a plan view in section ofthe relief valve of the pump of Fig. 9, the view being taken along line1010 thereof and looking in the direction of the arrows. at the endsthereof; and

Figs. 1 1, 12, 13 and 14 show the details of the side sealing platesfor'the pump of Fig. 7;

' counterbore 24 adjacent bearing 23, serves to prevent E i B Q theestatio the P F SuIe'eXerted:

dirt from entering the pump and the fluid contents of the pump fromescaping out of the pump alongshaft 22 On the .righthand-end of shaft22, as viewed'in Fig:- I I 2,'is formed a gear 26- disposed in a chamber27 formed? as a circular: recess inthe end of casting 20. Adjacent-1gear 26, and meshing therewith, is :a second gear 28' mounted on astub'shaft 29 one end of which is suitably supported in vhousing 20L Forease of manufacture, gear s' 26 and:28rmay.Ib e"made 'of the Samediameter and Width? Circular recess 27 is made a closed chamber by theapplication of an end cover 30 to the right hand side (Fig. 2) ofhousing 20, said end cover being secured thereto by a plurality ofmachine screws 31 (Fig. 1). Chamber 27 is further partitioned by ashroud 34 into a low pressure or inlet chamber-.32 and a high pressureor outlet chamber 33, said shroud cooperating with the tips of the gearteeth of the gears 26 and 28 to effect this partitioning. Shroud 34 isof the type disclosed and claimed in my copending application, SerialNo, 341,272, filed March 9, 1953, now Patent No. 2,742,862, for FluidPump, and comprises preferably a single piece of resilient deformable'material having elastomeric properties, such as rubber, synthetic ornatural, or a combination of the two, of a'thickness substantially equalto the width of the. face of the gear teeth (that is, measured along theaxis of the gear) and a configuration such that it will contact theouter periphery 35 of chamber 27 and the tips of the teeth of gears 26and 28 adjacent thereto. High pressure chamber 33 is defined, in part,by a groove 36 extending axially of shroud 34 and disposed symmetricallywith respect to gears 26 and 28. The side walls of the groove areexposed to the fluid under pressure in chamber 33, the pressure causingthe shroud to be distorted against the outer peripheries of the teeth ofgears 26 and 28 thereby to assist in maintaining a fluid-tight sealbetween the shroud and the tips of the teeth of gears 26 and 28.

End cover 30 is formed with an inlet opening 37 and an outlet opening38, said inlet opening communicating with chamber 32 and the outletopening communicating with chamber 33'. Inlet opening 37 may beconnected by suitable piping or tubing to a tank containing the fluid tobe pumped such as diesel oil, and outlet opening 38 may be connected bysimilar piping or tubing to the fuel injection system of the internalcombustion engine with which the pump is to be used. Since the devicesto be connected to the pump are not part of this invention, they are notshown nor described in detail herein.

As described more fully in my aforesaid copending application, SerialNo. 341,272, shroud 34 contacts the tips of the teeth of gears 26 and 28with a very light, but nevertheless firm contact so that the shroud iscontinually wiped by the gear teeth as the gears are rotated, the wipingaction being made possible by the slight deformability of the materialof the. shroud.

The sides of the gears are sealed by a pair of bimetallic discs 39 and40 disposed one on either side of gears 26 and 28. Each said plate iscomprised of a relatively thick sheet of steel 41, 42 to which is weldedby pressure under heat, or otherwise, a relatively thin sheet of bronze43, 44, respectively. This provides an appropriate material of dilferentcomposition to run against the steel of the gears to prevent spallingand undue wear of both the bears and the plates. The steel backingprovides the necessary strength for the plates.

An opening 45 is provided in plate 39 through which shaft 22 may pass.Additional openings 46 and 47 are formed in plate 39, opening 46communicating with low pressure chamber 32, and opening 47 communicatingwith high pressure chamber 33. An opening 48 in plate 40 establishescommunication between inlet opening 37 and low pressure chamber 32, andan opening 49 establishes communication between high pressure chamber 33and outlet opening 38.

It is contemplated that the fluid under pressure to be pumped willsupply a part, at least, of the force necessary to maintain plates 39and 40 in close sealing contact with gears 26 and 28. To this end, cover30. is. relieved over an inverted T-shaped area 50 (see Fig. surroundingoutlet opening 38 and overlying pressure chamber 33. As may be observedfrom Fig. 5, the relieved area overlies approximately 180- of arc ofeach of the gears 26 and 28,. including the portion of the gears whereinthe teeth. are in mesh with one another.

The boundary of area 50 is defined by a groove 51 in which is disposedan endless ring 52 of elastomeric material, preferably having anunstressed cross sectional configuration of a circle. For this purposeany of the presently commercially available O-rings having theappropriate length, composition and hardness of material can be deformedto take. the shape of groove 51. The depth of groove 51 is slightly lessthan the diameter of the radial cross section of the O ring, such thatthe ring is compressed when cover 30 is fastened to housing 20.

It may be observed that fluid under pressure entering area 50 betweencover 30 and plate 40 will exert a pressure against said plate 40 in anaxial direction relative to shaft 22 thereby urging said plate againstthe sides of gears 26 and 28, and that said gears, in turn will be urgedaxially against plate 39 and will hold said plate 39 against the radialsurface 53 of recess 37. By limiting the pressure area 50 to as small asection of the gear size as possible, a satisfactory seal is obtainedwithout an undue amount of friction being developed between the platesand gears, thereby increasing the mechanical efiiciency of the pump.

It is contemplated that, in accordance with the objects of thisinvention, the pressure of'the fluid leaving the pump through outletopening 38 will not exceed a predetermined value. This limitation in theoutput pressure is brought about by the provision of a relief valve 54communicating with opening 47 in pressure chamber 33. Said relief valveis comprised of a hollow cylinder having one end 55 closed and formed atits exterior with an annular knife edge 56 disposed around the outerperiphery thereof. Said knife edge is preferably arranged concentricallywith respect to opening 47 and bears against the exposed surface ofsteel plate 41 to form a seal therewith.

Valve 54 is axially reciprocable in a circular recess 57 in housing 20disposed with its axis parallel to the axis of shaft 22 and providedwith a vent opening 58 communicating with counterbore 24. Circularrecess 57 is connected by a passageway 59 to opening 46 in plate 39 andthence to chamber 32 which, as stated previously, is the low pressurechamber in communication with the tank or other supply of liquid fuel.Additional passages 60 and 61 may be provided for the purpose oflubricating bearing 23 and shaft 22. A spring 62, calibrated for therelief pressure desired, is compressed in recess 57 between the bottomof the recess and the closed end 55 of valve 54. Said spring holds valve54 in fluid sealing engagement with plate 39 until the pressure inchamber 33 exceeds the maximum pressure desired in the fuel line leadingfrom said chamber.

It is contemplated that shaft 22 will be connected to a suitable sourceof power somewhere on the engine to be supplied with fuel by the pumphereinabove described. When so connected and driven shaft 22 will rotategear 26 which, in turn, will rotate gear 28. Assuming that the directionof rotation of gear 26 is counterclockwise (Fig. 4) and that of gear 28is clockwise, fluid will be picked up between the teeth of the gears,confined by shroud 34, and carried to chamber 33 wherein the entrance ofa tooth of one gear into the space between adjacent teeth of the otherwill create a pressure in chamber 33 to cause the fluid to flowtherefrom. Said fluid under pressure will act upon end 55 of reliefvalve 54, and when the pressure exceeds that exerted by spring 62, valve54 will be pushed off plate 39, thereby opening chamber 33 to passageway59. The excess fluid thus enters the low pressure chamber 32 and isagain circulated through the pump past valve 54 and through passage 59to low pressure chamber 32. This circulation of excess fluid to maintaina predetermined pressure in the outlet for high pressure chamber 33continues as long as the demand for the fluid pumped does not exceed thesupply. The presence of fluid under pressure. in chamber 33 and inrelief area 50. results in pressure of plate 40 against gears 26 and 28and of these gears against plate 39, thus creating a seal the internalcombustion engine to stop the operation of V the engine, the operationof the engine, either by a push of the vehicle while it is drivinglyconnected to the engine, or by operating the starter for the engine,will turn the pump gears 26, 28 and eventually clear out all of the airin the system. a f

The form shown in Figs. 7 to.14, inclusive,'is designed forusewithinternal combustion engines using'volatile fuel such as gasoline,the fuelbeing aspirated in a carburetor and fed to the carburetor undera maximum pressure offive pounds per square inch. As shown in Fig.

8, thedevice comprises, in general, a pump 63 made in accordance withthe teachings of this invention having a pressure regulating valve 64and a pressure responsive cutoif valve 65 controlling the outputthereof.

Pump. 63 is comprised-ofa housing 66 which extends into an aperturedboss 67 in the housing 68 of a' drive source for the pump, such as anengine governor and distributor housing having a geared outlet 69 (Fig.7), for a tachometer drive or the like. Said'outlet 69 includes a drivengear 70 pinned to the left handend (Fig. 7 )Iof the drive shaft 71 ofpump 63. Said shaft 71 drives gear.

72 of the pair of gears constituting the pressure-creating portion ofthe pump, said pair of gears being in .all we, spects similar to pumpgears 26 and 28 of Fig. 4. i The right hand endof shaft 71 as viewed inFig. .8

is. supported in housing 66 by an antifriction bearing 73 thelubricantfor which is prevented from travelling along shaft 71 to theleft into housing 68 by ashaftseal 74 disposed adjacent bearing 73andinterposed between shaft- 71 and housing 66. Said housing 66 is heldin, place relative to housing.68 by a clamp 75, one end of which isreceived in a groove 76 in housing 66. ,The clamping force is derivedfrom a nut 77 threaded on a stud 78 secured to housing 68 and bearingagainst clamp 75. Movement of housing 66 in the direction of theclamping force is limited by a shoulder 79 on housing 66 abutting upon aflat surface machined in'the side of housing68.

Y Gears 72 are disposed in a cylindrical recess. 80 opening into theright hand side (Fig; 8), of housing 66,

. recess 80 being covered by a spacer plate 81 and by the housing 82,for the pressureregulating and cutoff'valves 64 and 65. respectively.Between gear-:72 and the bottom surface 83 of recess 80 is disposed ,aside seal .plate 84 made of bimetallic material,the principal portion ofthe plate being comprised=of 'steel and the portioncontactirig the sidesof the gears being bronze or some similar material which will run wellagainst the material of the gearswithout spalling or undue wear. Asshown in Fig. 11 plate.84 is provided with an opening 85 through whichshaft 71 may extend, and with a second opening 86 through which the studshaft (not shown) for the driven gear of the pump may similarly extend.Grooves 87 and 88 ,extendin'g radially from openings 85 and 86,

respectively, along the surface .of the bronze portion to the outerperiphery of disc 84 serve to prevent a.build-- up of fluid underpressure between the sides of the gears and the side sealplate as-w ellas to conduct a portion of the fluid to1be pumped to the bearing 73 andto the stud shaft to provide lubrication therefor.

. ,A shroud 89, made of an elastomer' such'as rubber, eithernatural orsynthetic or a combination of the two and having satisfactory wearqualities, is inserted in recess 80. btween the gears and .theyhousing.Said shroud may beideutical inevery respect to shroud 3.4 atria-. a

1 Between the'gears 72 and spacer 81 there is disposed 'a" bimetallicside seal plate in the form of a disc 90 ing '91 is provided in plate 90through which fluid to be pumped is admitted to the inlet side of recess80. A somewhat, greater than semi-circular opening 92'is formed in plate90 below opening 91. Said opening .92 is adapted to be filled by asimilarly shaped insert 93 (Fig. 13) made of the same material as plate90 and having an opening 94 therein constituting the outlet opening forthe pump. A second opening 98 is provided through which the stub shaftof the driven gear passes. It is understood, of course, that the bronzesurfaces of plates '90 and 93 are disposed adjacent the gears 72 toprovide a suitable running face therefor.

Overlying plates '90 and 93 is a flexible diaphragm 95, preferably ofthe same material as shroud 89, having an opening 96 aligned withopening 94 and an opening 97 aligned with opening91. As will behereinafter described in detail, opening. 97 is-theinlet opening for thepump and hence is connected through suitable conduits and pipes to thesource of supply of the fluid being constituting the inlet opening forthe pump, a pressure relief valve opening 100, and with a pump outletopening 101. As shown in Figs. 8 and 14, the portion of spacer 81overlying plate 93 is relieved to form a chamber 102 into which thefluid under pressure coming from the pumpmay flow. Said fluid underpressure acts upon that portion of diaphragm which overlies plate 93 andserves to'urge such portion, and plate 93, toward the gears 72. -Saidgears, in turn, are free to move to the left as viewed in Fig. 8 againstside seal .plate 84, and to hold the latter against bottom 83 of recess80. This results in aneffective seal for the sides of the gear teeth 3housing 82 may be used to seal all of said passages from the exterior ofthe pump as well as from one another.

Valve housing 82 is comprised of a substantially cylindrical portion 105having its axis disposed transversely of the axis of pump shaft 71, aplate 106 spaced from cylindrical portion 105 and abutting on spacer 81,and an intermediate connection portion 107 between plate 106 andcylindrical portion 105. A through bore 108 is formed in portion 105,the bore being closed at its lower end, as viewed in Fig. 8, by a bolt109 and provided at its other end with spaced bearing bushings 110 and111 within which is adapted to reciprocate a valve 112. An 0 ring seal145 is disposed between bushings 110 and 1 11 to prevent,the fluid beingpumped from escaping to the exterior of valve 65.

The upper end 113 of valve body portion 105, as

viewed in Fig. 8, is belled outwardly and upwardly and;

having a flange 117 is disposed on diaphragm 115 on the side thereofopposite flange 114, flange 117 being of substantially the same size asflange 114 and being secured to the latter by cap screws 118 which clampthe peripheral region of diaphragm 11,5 'toflange 114.;

The. upper end of valve 112 as viewed in Fig. 8 extends throughdiaphragm 115 and terminates in a shoalder 119. An apertured plate 120is placed on the side of diaphragm 115 opposite shoulder 119 and is madeto compress diaphragm 115 against said shoulder 119 by a nut 121threaded on valve 112.

It may be apparent that the flared upper portion of body 105, dishedcover plate 116 and diaphragm 115 constitute a pressure responsive motorfor reciprocating valve 112 in the cylindrical portion 105 of the valvehousing. It is contemplated that the chamber 122 formed betweendiaphragm 115 and dished plate 116 will contain the fluid the pressureof which is to be utilized to control the operation of valve 112.Chamber 123 on the other side of diaphragm 115 is vented to atmosphereat 124. Access to chamber 122 is gained from the exterior through athreaded opening 125 formed in an appropriate boss located eccentricallyof the center of valve 112.

' Cover plate 116 also serves as a limit stop for the upward movement ofvalve 112 and said valve is constantly urged upwardly against plate 116by a spring 126 retained between the head 127 of a needle valve 128 andan axially slidable bushing 129 surrounding needle valve 128 and servingto center said valve in the cylindrical portion 105 of the valvehousing. The upper end of bushing 129 abuts on the lower end of valve112 so that the pressure of spring 126 is transmitted directly to valve112 through bushing 129. It is contemplated that spring 126 will be soselected as to provide the requisite pressure to overcome the totalpressure on diaphragm 115 produced by the fluid in chamber 122 up to apressure of five pounds per square'inch and to yield under totalpressures produced by unit pressures in excess of five pounds per squareinch.

Chamber 102 adjacent diaphragm 95 is connected to bore 108 by apassageway 130 terminating below bushing 111 and above bushing 129 sothat the fluid enters bore 108 around valve 112. Said valve 112 has anaxial passage 131 formed therein which extends throughout its entirelength and is connected by cross passages 132 in shoulder 119 to chamber122. A plurality of radially extending grooves 133 is formed across theupper end of bushing 129 and constitute passages for admitting fluidfrom passageway 130 around valve 112 into bore 108, and from bore 108through said grooves 133 to the central passageway 131 in valve 112. Thefluid may then flow through cross bores 132 into chamber 122 and thencethrough opening 125 and suitable pipes to the carburetor or other fuelflow regulating device of the engine.

Chamber 102 is also connected through opening 100 in spacer plate 81 toa cylindrical valve chamber 135 in which is axially slidable a reliefvalve body 136. Said body is hollow and has nested therein a compressionspring 137 which is compressed between the bottom of the chamber and thevalve and serves to urge said valve continuously against spacer plate81. Contact between valve body 136 and spacer plate 81 is limited to aknife edge 138 formed around the periphery of valve body 136. Thisinsures continuous contact with the plate around the periphery of thevalve and also to provide a larger area of the valve against which thefluid under pressure issuing from opening 100 may act. The chamberbehind valve body 136 is vented by a small drilled passageway 139 whichconnects the chamber to a vent chamber 140 serving also as the vent forthe valve body 136. Spring 137 is setfor a maximum fluid pressure of 20to 30 pounds per square inch so that when the pressure of the fluid inchamber 102 exceeds the maximum spring pressure, valve body 136 will belifted oif its seat against the action of spring 137 andwill allow fluidto escape into ventchamber 140 from which it may be conducted through asuitable passageway 141 (Fig. back to the fuel supply tank.

8 The fiiel inlet opening is formed in a boss 142 (Fig. 9) disposed inthe side of cylindrical valve body portion and the fuel is conductedthrough a transverse opening 143 therein through passage 144, opening 99in spacer 81, opening. 97 in diaphragm 95, and opening 91 in side sealplate 90 to the inlet chamber for the pump.

One of the conditions under which the pump of Figs. 7 to 11 may berequired to operate is that obtaining when the entire fuel systembetween the pump and the engine is substantially dry and the engine isbeing turned over by its starter mechanism. During this relatively slowrotation of the engine and its distributor shaft, gear 70 and shaft 71will similarly be rotated at a relatively low speed. Due to the highvolumetric efliciency of the pump, however, a definite vacuum will beestablished in the intake side of the pump, thereby reducing thepressure in the intake passages below atmospheric and causing fuel tostart flowing from the tank through the passages to the pump. Meanwhile,on the pressure side of thepump the air will be pressurized and willforce its way to chamber 102, passageway 130, radial grooves 133 andcentral passage 131 through cross bores 132 into chamber 122. Fromchamber 122 it will be forced into the float chamber of the carburetorwhich at this stage is empty, and accordingly the float valve is open,thereby allowing the air to pass freely out into the atmosphere. Some,of course, will find its way into the engine because of the suctioncreated therein and in the intake manifold connected to the carburetor.

When the liquid fuel reaches the pump from the tank it will take thesame path taken by the air as described above, except that it willremain in the float chamber and will gradually fill the chamber. Whenthe float chamber is filled, the float valve therein will close andpressure will then be built up in chamber 122, forcing diaphragm and itsassociated valve 112 downwardly against needle valve 128. When saidneedle valve 128, passes radial grooves 133 and finally closes saidpassages, pressure in passage 'leading to grooves 133, and in chamber102 will increase until the pressure against valve 136 overcomes spring137, and the fluid is then vented through chamber and passage 141 backto the tank. Since the inlet and outlet passages are separated there isno recirculation of the fluid, whether liquid or vapor, and hence theconditions under which a vapor lock is created are substantiallyeliminated or avoided. Any small air bubbles entering the pump with theliquid will be moved on out through the pump to the carburetor and sincethe condition of the carburetor is governed by a float valve which inturn'is dependent upon the amount of liquidpresent and not at all uponthe quantity of air or vapor which may pass therethrough, the floatvalve will remain open until the air bubbles escape and the floatchamber is filled with liquid fuel. 1

It may be apparent that both forms of pump described above provide apositive movement of air vapor, liquid fuel, or combinations of thesefluids through the pump and henee the, conditions under which a vaporlock occurs are minimized, if not altogether eliminated. The pumps aresmall, require little power, and are durable.

It is understood that the foregoing description is illustrative ofpreferred embodiments .of this invention and that the scope of thisinvention is therefore not to be limited thereto but is to be determinedby the appendedclajms. 4

I claim:

A ea t p pump c mp i a housing having a cylindrical recess therein, apair of intermeshing gears dispose w thin sa d ece ean for driving 1 ofsaid gears, ar d means for dividing the recess into inlet and outleteharnbers with respect to the gears, said means Qmprising a resilientdeformable shroud disposed within said recess and contacting the tips ofthe gear teeth over less than of arc of each gear, a side seal plateadapted to contact the sides of the gears on one side thereof, and aside seal plate for sealing the other side of said gears, saidsecond-mentioned side seal plate extending across said cylindricalrecess and having an open ing therein overlying the outlet chamber ofthe pump, an axially movable insert inside the opening, meanscoextensive with the recess and contacting the housing around theperiphery of the recess for sealing the insert with respect to the saidsecond-mentioned side seal plate, and means for subjecting the side ofthe insert opposite the side contacting the gears to the pressure ofthefiuid in the outlet chamber.

2. A pump as described in claim 1, said means for sealing the insertwith respect to the plate comprising a diaphragm overlying the plate andinsert, a rigid cover plate for the recess, and means for securing thecover plate, diaphragm and second-mentioned side seal plate to thehousing, the pressure from the outlet chamber acting upon the diaphragmto urge it against the insert.

3. Apparatus for transferring fluid from a source of supply comprising ahousing having a cavity therein opening on a side of the housing,intermeshing rotatable pump gears in the cavity, means sealing ofiportions of the gears to establish inlet and outlet chambers in thecavity for the fluid, a spacer plate overlying the sealing means andhaving two outlet openings in communication with the outlet chamber andone inlet opening in communication with the inlet chamber and with thecourse of supply, means on the housing establishing fluid communicationbetween the inlet chamber and one of the two outlet openings incommunication with the outlet chamber through the source of supply, anda pressure relief valve in the said one of the two outlet openingsnormally closing said'one of the two outlet openings.

4. Apparatus for. transferring fluid from a source of supply comprisinga housing having a cavity therein opening on a side of the housing,intermeshing rotatable pump gears in the cavity, means sealing 'otfportions of the gears to establish inlet and outlet chambers in thecavity for the fluid, a spacer plate secured to the side of the housingover the cavity and overlying the sealing means, said spacer platehaving two outlet openings in communication with the outlet chamber andone inlet opening in communication with the inlet chamber and with thesource of supply, a second housing secured to the first housing over thespacer plate and having a passage communicating one of said outletopenings with the inlet opening through said source ofsupply, and valvemeans in the second housing normally closing the said passage andresponsive to the pressure of the fluid in the outlet chamber forlimiting the pressure of the fluid in the outlet chamber.

10 5. Apparatus as described in claim 4, said second housing having anexterior opening and a passage connecting the other of said outletopenings with the exterior opening, and a cut-01f valve in the secondhousing for closing the other of said outlet openings, said cut-offvalve being responsive to the pressure of the fluid in the exterioropening.

6. Apparatus for transferring fluid from a source of supply comprising ahousing having a cavity therein openin on a side of the housing,intermeshing rotatable pump gears in the cavity, means sealing offportions of the peripheries of the gears and dividing the cavity into.inlet and outlet chambers, a plate overlying the cavity and having anopeningexposing the outlet chamber and adjacent portions of the gearsand sealing means, a second plate in the opening, a resilient diaphragmextending over the cavity including the second plate, and meansestablishing a third chamber exterior to the diaphragm overlying atleast a portion of the said opening in the plate, therebeing, alignedopenings in the second plate and diaphragm communicating with the thirdchamber exterior to the diaphragm to establish unit pressure in thethird chamber substantially equal to that in the outlet chamber wherebyto urge the diaphragm and second plate against the gears, and sealingmeans to provide a seal between the inlet and outlet chambers.

7. Apparatus for transferring fluid as described in claim 6, said meansestablishing a third chamber comprising a spacer plate having a pair ofoutlet openings leading from the third chamber, a second housing securedover the spacer plate, and a valve in the second housing movable againstthe spacer plate to block one of said outlet openings, said housinghaving a passage connecting the said one of said outlet openings withthe inlet chamber through the source of supply, such that when the valveis moved to uncover the said one of said outlet openings, fluid isby-passed from the outlet cham her to the inlet chamber.

References Cited in the file of this patent UNITED STATES PATENTS DeskaNov. 19, 1957

